BANGOR, Maine — A Bangor firefighter’s leather helmet disappeared late Friday at the Bangor State Fair where he was working a four-hour shift with others just in case there was an emergency at the fairgrounds.

After a plea seeking its return was posted on Facebook, the black leather helmet bearing the shield No. 36 was returned to the Main Street station on Saturday evening, after its owner, David Rudolph, was off duty.

Rudolph had all his turnout gear with him near the command vehicle at the fairgrounds, Capt. John Prentiss said Sunday morning as firefighters unrolled and tested hoses behind the Main Street station.

“We asked people to keep an eye out for it, and everybody spread the word, and it was posted on Facebook by someone,” Prentiss said. “It was found Saturday between the raceway and the agricultural section of the fairground in the long grass. It was dropped off at the station Saturday night.”

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The Facebook posting asked that the helmet be returned to the Main Street station. It also said that “no questions” would be asked about how the person who returned it came to possess it.

The captain said that most firefighters purchase their own leather helmets, which cost about $650, and wear the same one for their entire careers. Prentiss said he’s had the same leather helmet for 27 years.

“We’re all grateful it’s back and didn’t show up on ebay or Craigslist, which is what we expected,” Prentiss said.

Rudolph was not scheduled to work again until Wednesday. Efforts to contact him were unsuccessful Sunday morning.

The original fire cap, invented by Jacobus Turck of New York City in 1731, had a round shape with a high crown and a narrow rim, according to FireFighterShields.com, the website for a Virginia firm that makes the shield for the firefighters’ helmet.

Between 1821 and 1836, Henry Gratacap, a luggage maker and volunteer firefighter, designed his own leather helmet for firefighters that was later named the “New Yorker,” the history on the website said. Adopted by the New York City Fire Department during the late 1800s, the “New Yorker” was an eight-comb design, meaning that it had eight different segments. The leather used for the helmet was the same used by Gratacap for his luggage design, which was specially treated to withstand wetness without rotting. These helmets often were worn backwards to protect the firefighter’s face against heat.

The helmets worn by today’s firefighters are similar to the early model.

“The leather helmet is the traditional symbol for the fire service,” Assistant Fire Chief Tom Higgins said Sunday. “It’s steeped in tradition and an integral part of our turnout gear.”

CORRECTION:

An earlier version of this story erroneously stated the missing helmet was No. 35. It was No. 36.